1. Field of the Invention
The present invention relates generally to aircraft collision avoidance, more specifically to aircraft ground collision avoidance, and most specifically to cross-platform automatic aircraft ground collision avoidance.
2. Description of the Related Art
The Office of the Secretary of Defense has required a reduction in the number of mishaps associated across defense aircraft platforms. Automatic Ground Collision Avoidance Systems (Auto-GCAS) have been tested on defense aircraft and have been demonstrated to reduce aircraft mishaps.
Auto-GCAS utilize digital terrain elevation data (DTED) to determine ground proximity. DTED is a product developed and maintained by the National Geospatial Intelligence Agency and is not produced to operate with Auto-GCAS. Therefore, Auto-GCAS requires manipulation and conditioning of DTED both prior to installing it in aircraft as well as in flight for proper operation of Auto-GCAS. The altered DTED in known as a digital terrain map (DTM).
However, due to the size of the DTM, many aircraft do not possess sufficient storage capacity and/or computing resources in their standard onboard systems in order to use the Auto-GCAS with the standard DTM.
One attempt to address this problem is disclosed in U.S. patent application 2007/0247350. The application discloses a method of reformatting terrain data to increase compressibility of the data. While this invention allows for significant compression of terrain data, it may not provide sufficient compression for certain aircraft. Further, this disclosure does not allow one to compress terrain data to different levels of compression. Also, the compressed data cannot be used in its compressed format. p A general attempt to provide more accessible map data is disclosed in U.S. patent application 2008/0238941. This application discloses a method of adding custom map content to maps. While it describes making custom three-dimensional maps based on elevation data, the application merely does so by using known mathematical algorithms to generate said maps (see paragraph 0055). However, it in no way describes a novel method, previously unknown, in order to more efficiently generate said maps in a way to use significantly less memory.
Therefore, it is desired to provide a system and method to significantly compress a digital terrain map for use in an Auto-GCAS system, with the flexibility to compress the DTM to different levels of compression and to use the data in its compressed format.